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Warming Waters Are Hot Topic

As the purple line for 2020 shows, temperatures measured at our Continuous Monitoring Station in Yarmouth, Maine, are setting records. Our staff, board, and volunteers are using data from the station in conversations with community members and decision makers to explore what we need to do to address and adapt to changes that are happening.


Day after day, we watched temperature records being set. This year has been hotter than usual. Out of the first 243 days of this year, January through August, 2020,  132 days exhibited a daily average temperature higher than established for that day in any of the prior four years, 2016 – 2019.

“While warm water temperatures may have been great for swimming in the Bay,” says Staff Scientist Mike Doan, “there are significant downsides to warming water. Less oxygen, more invasive species, changes in the ocean food web, and the growth of nuisance and harmful algal blooms are all associated with warming temperatures.”

In addition to hourly data collected at the station, Friends of Casco Bay’s staff monitor another 22 sites around the Bay as part of our seasonal spot-checks. Those sites, too, have been extremely warm. Our offshore site in Broad Sound saw temperatures near 22°C [almost 72°F], and the upper New Meadows River had temperatures over 25°C [nearly 80°F].

Other researchers have noted similarly high temperatures offshore in the Gulf of Maine this year. In August, NOAA satellites measured an average sea surface temperature of 68.93°F, nearly reaching the record set in 2012.

These data are critical as we continue our advocacy work with the Maine Climate Council at the state level and Portland and South Portland’s One Climate Future initiative at the local level, to address and mitigate the impacts of looming changes.

“What we have been seeing this year reaffirms for me the urgency of our collective work to document change, address the root causes of climate change, and prepare for its consequences at community, regional, state, and national levels,” says Casco Baykeeper Ivy Frignoca.

What warming waters could mean for Casco Bay


This year has been one of the warmest on record. Why is that bad for the health of Casco Bay? Check out this short video as Staff Scientist Mike Doan takes a quick dive into our Continuous Monitoring Station’s data to share one of the biggest reasons we should be concerned about warming waters.

As always, you can always find our most recent Continuous Monitoring Station data on our website.

In case you missed them, here are the first three videos of Mike’s Field Notes:


Donate to Climate Change and Casco Bay Fund

Friends of Casco Bay created the Climate Change and Casco Bay Fund to be used over the next ten years to understand how Casco Bay is being affected by climate change. We are launching and maintaining three oceanographic Continuous Monitoring Stations at three coastal sites around the Bay to collect data on water quality conditions. Communicating those changing conditions to our community is paramount for advocating for policies and actions needed to adapt to and mitigate the effects of climate change. You can read all about this work and the fund to support it here


Keeping up with the Casco Baykeeper

For Casco Baykeeper Ivy Frignoca, the summer has been full of moments of concern and moments of magic.

How was your summer?

Summer means being on the Bay! Staff Scientist Mike Doan and I continued to collect our seasonal data on the health of Casco Bay by land and sea. As we collected water quality data, we had the opportunity to speak with people who rely on the Bay for their livelihoods and deepened our conversations about what we were seeing and how to use our data to shape our advocacy work.

How did the pandemic affect your Baykeeping work this summer?

We kept up with water quality monitoring by limiting crew on our Baykeeper boat, R/V Joseph E. Payne, to just two of us at any one time. We continued to collect hourly data from our Continuous Monitoring Station. We kept up with all water quality monitoring, including responding to the unexpected.

What changed and what we really missed was inviting others out on the boat with us. We love using the boat as our summer office, a way to gather people who can work together to find solutions to problems that impair the health of the Bay. It makes a big difference to view issues from the water and have people aboard with expertise and authority to address problems. We couldn’t do that this year.

What was the most concerning issue you saw this summer?

What stands out was a day in mid-July when we saw a large area of brownish water extending from the mouth of the Royal River. Mike and I thought it might be a phytoplankton bloom. But when we put our sonde in the water, it measured low salinity levels that were startling, extending out almost to Moshier Island. We had captured a stormwater plume from a recent major rainstorm.

What also stands out was how uniformly high water temperatures remained this summer. Broad Cove saw temperatures near 20°C [70°F] and the upper New Meadows River had temperatures between 25-26.5°C [nearly 80°F].

What we saw this summer reaffirmed for me the urgency of our collective work to document change, reduce the causes of climate change, and prepare for its consequences at community, regional, state and national levels.

How about some of your favorite moments of the summer?

There are always moments of astounding beauty on the Bay. Every day on Casco Bay is magical. Watching terns feeding, bald eagles soaring above the boat, leaping sturgeons in a school of bait fish, or the sunlight reflecting like a mirror on the water are moments of magic that underlie why we work to protect this amazing place.

I really enjoyed becoming more deeply connected to our volunteer Water Reporters. Their posts track important issues and give us a great view of what is happening around the Bay. Working with Community Engagement Coordinator Sarah Lyman, I spent some socially-distanced time with Water Reporters, following up with them as they tracked algae blooms, marsh conditions, reported pollution, and posted about other changes they were seeing in the Bay. It’s awesome knowing that there is a whole team of people in the community helping with our Baykeeping work.

How rainstorms affect the Bay

Today’s rain reminds us that heavy rainstorms can deliver a significant insult to the health of Casco Bay.

Rainwater runoff resulting from intense storms flows into the Bay, bringing with it a host of pollutants including nitrogen, pesticides, oil, and heavy metals. If rainfall is heavy enough, the large dose of freshwater can temporarily lower the salinity, or saltiness, of the Bay.

This year we experienced a long stretch of dry weather through May and into June, which was followed by almost three inches of rain in just two days in late June. This combination created conditions that brought a large amount of freshwater into the Bay through both runoff and increased river flow. The river flow increase can be seen in the United States Geological Survey river gauge data from the Royal River. The Royal empties into Casco Bay near our Continuous Monitoring Station.

The graph above compares the flow of water in the Royal to the salinity at our Station in Yarmouth. The increase in fresh water following the storm causes a decrease in salinity at the station. It takes significant amounts of freshwater to dilute the water in the Bay. This suggests large amounts of stormwater runoff deliver pollutants to the Bay.

The increased river flow was still visible into mid-July. While out conducting our Seasonal Water Quality Monitoring on July 15, Staff Scientist Mike Doan and Casco Baykeeper Ivy Frignoca measured salinity values of 6.4 parts per thousand (ppt) at the mouth of the river where values are typically around 29.0 or 30.0 ppt. As they moved away from the river mouth and out toward deeper water, values were still lower than usual at 12 to 15 ppt.

In the period of time following the storm, we saw a dramatic increase in blooms of nuisance algae. This is potentially the result of increased nutrients in the stormwater runoff, as well as high water temperatures.

As Casco Bay continues to get warmer and we experience more frequent and intense rain storms because of climate change, we may see more pollutants and more nuisance algal blooms in the Bay.

This is one of the many reasons why Friends of Casco Bay launched the Climate Change and Casco Bay Fund, which will help us put two more Continuous Monitoring Stations in the Bay, one near Portland and one near Harpswell, and operate all three stations for ten years. The $1.5 million Climate Change and Casco Bay Fund will be used over the next decade to understand the ways in which our waters are changing, while we engage the community in assessing and adapting to climate change. You can read more about the Fund and our 10-year plan here.

What can you do about stormwater pollution?

  • Did you know that the fertilizers and pesticides you put on your lawn may end up in Casco Bay and contribute to these problems?
  • Keep pollutants from entering the Bay by reducing or eliminating the fertilizers and pesticides you apply to your lawn.
  • Become a Water Reporter. Our volunteer observing network tracks the spread of algal blooms around Casco Bay. We use that information to alert the State to changes in our coastal waters.
  • Make a donation to support the Climate Change and Casco Bay Fund.

Casco Bay is heating up

Seem hotter than usual? Yes, indeed.

Our Continuous Monitoring Station has been collecting hourly data on the health of the Bay for more than four years.

Data from the station show that this summer has been the hottest one we have recorded since our “Cage of Science” has been in the water.

This graph compares water temperatures from 2016 to this month. The lavender-colored line represents the daily averages for this year.

Staff Scientist Mike Doan says “The data are concerning. This summer’s temperatures were on average the warmest we have seen at the station.”

You can find the most recent data for all the parameters we measure at our Cage of Science here.

In addition to collecting hourly data, for nearly 30 years, we have been spot-checking sites in the Bay. The temperature data from our three Sentinel Sites (see graph below for annual average, data collected May through October each year) show an upward trend as temperatures in Casco Bay have risen by 2.4° Fahrenheit [1.3° Celsius].

annual temperatures graph 2019

“Casco Bay is changing and changing quickly,” reports Executive Director Cathy Ramsdell. “That’s why we have launched the Climate Change and Casco Bay Fund, which will help us put two more Continuous Monitoring Stations in the water, one near Portland and one near Harpswell, and operate all three stations for ten years.”

The $1.5 million Climate Change and Casco Bay Fund will be used over the next decade to understand the ways in which our waters are changing, while we engage the community in assessing and adapting to climate change. Friends of Casco Bay has raised 87% of its goal for the Fund. You can read more about the Fund, our 10-year plan, and make a secure donation here.

What’s green, microscopic, and makes ½ our oxygen?

What’s green, microscopic, and makes half of the oxygen we breathe? Phytoplankton, the tiny algae at the base of the food chain, that’s what!

Measurements of chlorophyll — the green pigment that enables plants and algae to photosynthesize — provide an estimate of how much phytoplankton are in our coastal waters.

In this third edition of Mike’s Field Notes, Staff Scientist Mike Doan shares what he sees when he looks at our Continuous Monitoring Station’s most recent chlorophyll data. You can watch the three-minute video below.

In case you missed them, here are links to the first two videos of Mike’s Field Notes:

Mike gives a tour of our Continuous Monitoring Station.

Mike discusses how warm our winter and spring have been.

30 years of success protecting the Bay

We were delighted to have more than 80 Friends of the Bay join us for our 30th Anniversary Members Annual Meeting on June 16. As Executive Director Cathy Ramsdell said during the event, we only wish we could have held it in person.

If you missed the event — or if you want to re-watch your favorite parts — we are providing you with links to the following videos:

In this 8 minute video, the Casco Bay region’s Congressional Delegation, including Senators Susan Collins and Angus King and Congresswoman Chellie Pingree, share reflections on what 30 years of Friends of Casco Bay means to them and to our community.

In this 8 minute video, Cathy describes how our work to protect the health of the Bay continues. We may be socially distant from one another right now, but we remain connected to the Bay. Hear how our work continues.

Lastly, and perhaps most importantly, in this video Cathy shares our plans over the next decade and beyond to help our community address looming threats, and she announces the formation of the Climate Change and Casco Bay Fund for Technology, Science, and Community Engagement.

During the Annual Meeting portion of the event, Steve Bushey and Mark Green were elected to their first terms to the Board of Directors, Malcolm Poole was re-elected to his second term, and Joan Benoit Samuelson and Tollef Olson were elected to their third terms. You can find the complete list of our Board of Directors here.

Stay tuned. Soon we will announce how you can take part in our second 30th anniversary event, which will be held in late July.

Thank you for your support over the past 30 years and for joining us on our voyage toward a healthier, more protected Bay in the decades to come.

Take a tour of our Cage of Science

What is this Cage of Science that Friends of Casco Bay keeps talking about? We invite you to join Staff Scientist Mike Doan out on Casco Bay for a short tour of our Continuous Monitoring Station. In this 2 ½ minute video, Mike shows off the high-tech components of the station and shares why its stream of data is so important to our work.